Gumminess is the quality of being sticky or tough, and there are several synonyms that can be used to describe it. One such synonym is viscosity, which refers to the thickness or stickiness of a liquid or substance. Another word that can be used to describe gumminess is adhesiveness, which refers to the ability of a material to stick to other surfaces. Cohesiveness is another synonym for gumminess, and it refers to the strength and bonding capability of a substance. Finally, tackiness is another synonym for gumminess, and it refers to the ability of a substance to stick to surfaces, especially when pressure is applied.